Steam-boiler.



No. 842,024; PATENTED JAN. 22

H SGHOFIELD STEAM BOILER. APPLICATION FILED DEG.15,'1905.

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UNITED STATES EATENT OFFICE.

HARRY SOHOFIELD, OFLONDON, ENGLAND, ASSIGNOR OF ONE-THIRD TO SIDNEY JOHN ROSS AND ONE-THIRD TO OLIVER PRESCOTT MAOFAR- LANE, OF LONDON. ENGLAND.

STEAM-BOILER.

Specification of Letters Patent.

Patented Jan. 22, 1907.

To a whom it may concern:

Be it known that I, HARRY SoHoFIELD, engineer, a subject of the King of Great Britain, residing at 1 Bryantwood road, Drayton Park, London, N., England, have invented certain new and useful Improvements in or Relating to Steam-Boilers, of which the following is a specification.

This invention has reference to steam-boilers, especially to those having internal furnaces or flues, such as Lancashire and Cornish boilers, and relates more particularly to boilers in which cross-tubes are fitted in the said internal furnaces or flues.

In cross-tubes or water-circulation tubes as usually arranged the water in the center thereof is liable to remain idle and comparatively cold and dead, thus retarding the production of steam, since only the water near the circumference or side wall of the tube can come under the action of the flames and heated gases.

In order to obviate this disadvantage, according to the present invention the center part of the cross-tube or circulation-tube is occupied by a core, filling-piece, or plug, provided, preferably, with vertical inclined or spiral grooves, flutings, or corrugations, which serves to displace the idle or dead water of the cross-tube, leaving around it a relatively narrow or restricted water space or channel containing a thin body or jacket of water, which, being near the circumference of the tube, and therefore subject to the full heating eflect, becomes rapidly raised to boiling-point and is thrown into active circulation. Hence a very quick generation of steam is secured. The boiler becomes equivalent, in eflect, to a small tube-boiler, while preserving the advantages of the cylindrical or shell type of boiler.

As the cross-tubes or water-tubes usually become wider at the top, the core or plug, which may for distinction be termed a steaming-core, is made to correspond; but it may be of any desired shape in cross-sec tion or arranged in any convenient way in order. to vary the thickness of liquid between it and the wall of the tube at different points, as may be found desirable. For instance, it may be ribbed, fluted, or corrugated, if desired, vertically or otherwise.

the steaming-cores and cross-tubes may be arranged, though only one type would usually be employed in one and the same boiler;

Fig. 2 is a separate front elevation of the first cross-tubethat is to say, the one toward the left, Fig. 1; Fig. 3 shows the fillingpiece or steaming-core separately in elevation, the same being in this instance provided with ribs, corrugations, or flutings. Figs. 4 and 5 are respectively upper and lower end views of the said core. of the cross-tube with part of the wall thereof broken away to show the core in position. Figs. 7 to 10 are detail cross-sectional views, hereinafter referred to.

Referring first more particularly to Fig. 1, a represents the shell of the boiler, which may be of the well-known Lancashire or Cornish type. b is an internal flue or furnace of the usual kind, and c c c are crosstubes or circulationtubes. Inthe example shown these crosstubes are formed with a taper, so that they are wider at the top than at the bottom. They are provided with inletnozzles, hoods, or elbows d at their lower or narrower ends and outlet-nozzles or hoods e at their upper or wider ends for promoting and directing the circulation of water, these hoods being Fig. 6 is a side view securely clamped in position,for eXample,by

nuts f ,working on tie-rods f, passed centrally down the cross-tubes c. Thesenozzles d and (2 may, as in Fig. 1, be both directed toward the front of the boiler in order to set up a longitudinal circulation thereinthat is to say, to cause the water to flow along the top of the flue toward the boiler-front and then back under the bottom of the flue. The fillingpiece or steaming-core, to which the present invention more particularly applies, is shown at g and may be of plain, circular, or other convenient shape in cross-section and has a taper corresponding to that of the cross-tube, or practically so. In the example illustrated, however, it is provided with straight or vertical ribs or ridges h, which divide the circumference into vertical channels, corruga- ICO tions, or flutings it all around it. ribs or ridges It fit close against the inner walls of the cross-tubes, so that the channels or flutings form, as it were, separate tubes of small cross-sectional area, and hence the w ater within them becomes highly heated and is rapidly thrown into energetic circulation, as occurs in what are known as small-tube or express boilers.

The ribs and flutings instead of being straight may obviously be made more or less inclined or spiral, if desired.

The steaming-core may either be solid, or it may have a suitable filling in its interior. It may, moreover, be hollow and simply have a closure, say, at the bottom, its interior being left full of water, which being allowed to re main idle will soon acquire a high temperature and will therefore not interfere materially with the rapid production of steam. Thus in the example illustrated in Fig. 4 in connection with the first cross-tube or circulationtubethat is to say, the cross-tube c the filling-piece is provided at each end with end plates or covers 9 to prevent the free circulation of water through the center of the core. The tie-rod f is passed centrally through these covers. Thus the arrangement is practically equivalent to a solid core without the inconvenience due to the weight of the solid metal in the latter.

The steaming-core or filling-piece may either terminate near the top of the furnace b, as in the arrangement shown in the crosstube 0, or it may be continued upward into the hood or nozzle 6, as shown in connection with the second cross-tube c. In the latter case the said hood may have a filling-piece g of its own adapted to fit onto and form a continuation of the main filling-piece, or the latter may be formed or provided with a bent-over extremity or elbow corresponding to the piece 9 Thisextremity 9 may be contracted or tapered to a point in the center of the mouth of the hood or nozzle 6, as shown in the example illustrated. According to another modification, as shown in connection with the third cross-tube 0 the upper elbow or hood 0 may be dispensed with, or rather it may be replaced by a short upright cylinder or nozzle 6, through which the filling-piece or core g may extend upward, as shown at g this extension 9 being either integral with the core or being a separate piece or block fitted thereon It is to be understood that although three cross-tubes are shown this is only for purposes of illustration and to show different modifications already, since the invention can be carried out with either kind separately.

Although in the arrangements above described the fillingpiece or core is referred to as being fluted or corrugated, yet in some cases the said core may simply be of plain he said r circular form in cross-section, as represented in Fig. 7, which is a detail cross-sectional view through the cross-tube on the line w of Fig. 6, but indicating a filling-piece without any fiutings or corrugati n. In tlns case the circumferential water-space in the tube becomes a plain annular channel or passage 7L2, corresponding, however, to the flutings or channels 71 and analogous to them in action. Moreover, the arrangement of the tube and core may, if desired, be such, for instance, that there is more liquid at the front of the tube where the fuel-gases impinge than at the rear, and with this object the core may be disposed toward one side eccentrically or otherwise, as shown in Fig. 8, which is a corresponding section to Fig. 7. It may also be desirable to make the area of the water space around the core approximately equal a" its upper and lower ends, and tins may be done either by makings the flutings h deeper toward their lower ends (compare Figs. 4 and 5) or by reducing the diameter of the lower end (see Fig. 10) of the core to a greater extent than would otherwise be the case. By the latter arrangement the width of the space 72. between. the tube and the core becomes greater at the lower part, Fig. 10, than at the upper part, Fig. 9, these in Figs. 9 and 10 being, respectively, cross-sections on the lines :v a: and y y, Fig. 6, thus compensating for the reduction in size or radius at the lower part and keeping the actual area h of the free water space or passage practically uniform throughout the length of the tube 0.

The core or fillingpiece may be of castiron, gun-metal, stamped sheet metal, or other suitable material and, as stated, may be solid or hollow, and its surface may be smooth or glazed, or even be enameled, to obviate the adherence of scale thereto.

In some cases the core or filling-piece may rest inside the tubes on radiallyprojecting points or rests, of which there may be, say, three at the top and three at the bottom, adapted to fit the taper of the tube.

Obviously the invention may be modified in a variety of ways without departing from the essential features thereof.

What I claim, and desire to secure by Letters Patent of the United States, is-

1. In a steam-boiler, the combination'of a longitudinal flue, cross-tubes for water ar-. ranged transversely of the said flue and open at top and bottom, and filling means extending approximately from the top to near the bottom of the cross-tube for confining the wa ter to the circumference of such cross-tubes, so as to form a thin annular body of circulating water inside said crosstubes, substantially as described.

2. In a steam-boiler, the combination of a flue, a cross-tube containing water, and means extending .approximately from the top to near the bottom of the cross-tube for forming an obstructed annular space inside said crosstube through which the water can flow directly upward from the space below the flue to the space above it.

3. In a steam-boiler, a water-tube, means inside said tube extending approximately from the top down to near the bottom of the latter for forming an annulus of circulating Water, and a hood at the top of said tube for directing the outflow of water therefrom, substantially as described.

4. In a steam-boiler, the combination of a cross-tube, means extending from the top down to near the bottom of the tube for forming an annular water-passage in same, and means for discharging the water from said tube into the water in the boiler, in a horizontal direction, substantially as described.

5. In a steam-boiler, the combination of a cross-tube, a core inside same extending from the topthereof down to near the bottom of said tube through which water cannot pass, such core having an annular space between itself and the cross-tube, and means for directing the water which flows out of the top of the tube and causing it to flow away in a horizontal direction, substantially as described.

6. In a steam-boiler, the combination of a cross-tube, a core inside same extending from the top down to near the bottom of the tube through which water cannot pass, such core having an annular space between itself and the cross-tube, and an elbow-shaped hood at each end of said cross-tube, substantially as described.

7. In a boiler, the combination of a longitudinal flue, a circulation tube extending across said flue, a filling-core within said tube, forwardly-directed nozzles extending within the boiler and carried by opposite ends of the tube, and' a tie-rod extending through the interior of the said core and exterior of the nozzles for retaining the latter in position on the tube.

a 8. In a steam-boiler, the combination of a longitudinal flue, a circulation-tube fitted across the ends of said flue, a filling-core with in said tube, forizvardly-directed nozzles at the upper and lower ends of said tube, and adapted to extend within the boiler for directing the flow of water, and a tie-rod passing through the core and nozzles for maintainthe same in position with respect to the ue.

In testimony whereof I have hereunto set myhand, in presence of two subscribing Witnesses, this 24th day of August, 1905.

HARRY SCHOFIELD.

Witnesses:

C. BARNARD BURDON, ALFRED NUTTING. 

